Manufacture of sodium cyanide



Patented Aug. 25, 1936 caries No Drawing. Application January 13, 1934, Ser al. NO- ififil ifi 1e ei ims. (ei- 23.1-19

T i nten ion r a es. to t e roduct on. of oranide more. particular y t the exenides o he lkali. metals, such as; sodium c ani e.

Ptoee ses veh enkhown and: used for the 5 production of alkali metal cyarnjdes, such proc;

esse be capable. oi the pr uc n a sati fa to jv gradev o odiu cyanide. f r examp but th a e ubject to ce tain disadvanta e such i -the neces ty or a curate and constant super:

tis o e o ntr oi th oces the relatively hi h cost of, aw material-s1. and the genera ly eoihu ieat d. ehar ete of t e operation itse f.

There has also been knpwn'a method.- 015 P1701 dup n a ka i ear h m tal. osten des. su h as call m ere iii by a, cheap. and e eetive pro edure.- T s roc s o si ts: e sential y. in providin a i t e, o al i m. e ariamiet and odium eh o= ide. tor xample, fu in the ome and rapidly ohilhe the roduct, w i h contains a. r latitelx large proportion of calciurncyanider This; proc, s hes a n mber of l lfilltt es that. it is a simple o e tion, wh ch is. ree ilu arried: out: and the pr d c s con in ously produced-r It does no equire k l d. wo kmen an the nroeess so simp and efie tiy -i V c The present. inventi n s. ntended to. p ovide a method of mak kelii metei-oyan des by a. impl che p: nt f ct v nt eess, wh r by t cost thereof will eeitee 1y. h dueec oyer the ol p o ess r r oii ht u i izedv the. Pr du tion of alkali metal cyanides. The present ent en. i elso it odeii ut ieees a raw m e e h e eium an e. de ained the, process above mentioned.

? Th n me h d nsists ssent al in firs r din lka i eart metal: c an de. such. as eale m cyanide. nd; con tin he; e h; an; lkal me a lt eten, aeid wh ch. s is e o f t ieeh insolubl alkal eet h. metal sa R Q rea on.- tek he. iaeei etw en said some Roun s he iHEiTQdEI-Wh heate t s e e tl eh emoete i rwh eh; i enera L in eien an the mi of.- he mol en. e:

? terials causes the desired reaction to take. l e, In said; reaction the alkali metal replaces the alkali earth metal in the cyanide and the alkali earth metal combines with the acid radical forming an insoluble compound.

The following is a more specific description of the operation of the new method. A mixture is made of a crude calcium cyanamid and sodium chloride in the proportion of about two parts of calcium cyanamid to one part of sodium chloride.

The mixture is heated in a furnace to cause 12 w h lt n o n oi on e o h. .15

iusio to ta p ace. where y a e etion oc urs between. the calcium exanamid and the free car boo whi h is pr sen n the eyar em d w e by it i trensi rm d into. eele um c an de. The sodium chloride is. a flux which assists, in the, 5 conversion oi the al ium ye amid int c anide and; Pr vides. a. re fl w ix ur which s tanned f m th iurnaee a d rapidly ooledhe res ltin Product s ssent a y a mixtur oi ca f cyanide, so ium chloride and varying quan: s. oi in r mpurit es su h as lime. carb n and th i e.-

29% ear-ts a .6% cal ium cyanide, made as above, deserihed may now he m xed w th about L29. pa ts Qt sodium arbonate. for examp e. and the mixture heated in a suitable furnace to a temp rature wh ch. may e above h m ltin oint oi: ne; r both o the ngredi ts, whereby ar ee io takes. n eee, i l ws V omen) hem co =2uecn+caeo its a r su t. th ite. is. formed sod um c anide. usii lx in t e mo t n. e. a w mo en so eh o tie. nd the contains in V ed i ion n o. this glid hlg llm, arb n e. a d/ r 2 oxide and; othe m ri e o mino ha tee en The molten mixture of sodium cyanide; and sod tto hloride may be separat d rom: the i soluble pu ities iva i us w ys;- o xam.- hle. t e molt n ixture the be all w t emain q i t. a suflieient len th o time and held; s; hi h e peratu to allow the insoluble solid. impurities to; settle to the hottom. tte whieh t e m lt n. ma ia may be tieeehte o t they: be te d and. h n worke 3 nto he; esir d. form,

s ee et fii ed lmiey -h de. omnojti h thehbetr ated' to e et i s even eeeo eh instead of ieez he nsolub eh ens fr m the molten portion I may cool the en mass and 40 shed. he same o a. suitable e e, e of fine es n ther-eeeei extn et es d um cyanide s s to ree i item notoel th h ele l Jmatten u eise tohi subsieh ii 1. o e sodium ehloi e, o othet l sal h s. wb ne tatio i' zweys. b M no neo tie le r as d s t b d; in my e. eeoheetioo; serial NoJtlihti filed February 17, 1934 and entitled Manufacture of sodium cyanide. As set forth in said application I utilize substantially anhydrous methyl 50 alcohol, containing a small amount of anhydrous ammonia, as a solvent. This mixture has the property of dissolving a relatively large proportion of sodium cyanide while dissolving substantially none of the other compounds contained in 55 the mixture. The solution is filtered and the solvent is evaporated and recovered, leaving behind it a substantially pure high grade sodium cyanide.

While I have above described a single specific example of the method of producing sodium cyanide, it is, of course, apparent that my invention is not limited to the making merely of sodium cyanide but other cyanides of similar character, including all of the alkali metal cyanides, may of course, be made in the same manner. given above several methods of separation and of purification of the sodium cyanide produced by the present invention and such methods are to be considered as illustrating a large variety of methods which may be used in the treatment of such cyanides. 1 I

In the description I have set forth a process in which the alkali earth metal cyanide in the solid state is mixed with the alkali metal salt also in the solid state and the mixture is fused. This exact procedure is not essential to the operation of my new method, as it is possible to use variations thereof with good results. In some cases it is not necessary to melt the materials as heating to incipient fusion or even to such a point that sintering begins, will be found suflicient to give the'desired reaction, particularly ifthe ingredients are finely divided and intimately mixed. In the alternative I may melt one of the ingredients and gradually mix with the same the other ingredient in solid form, thereby causing a gradual reaction with the formation of the alkali metal cyanides. As another alternative I may melt both of the constituents and mixthe two melts to give a molten product. 7

Or I may tap the molten calcium cyanide from the furnace as described above and mix the same while it is flowing from the furnace, withthe alkali metal salt either in the. molten orin the solid state, causing the reaction to take place immediately and to be completed prior to the cooling and. solidification of the resulting'product. The molten mixture may be caused to contact with the cooled surface of a rotating drum to solidify the same, after which it is scraped from the drum in the form of flakes.

In place of the sodium carbonate, which I have given above as an example of an alkali metal salt suitable for the process, I may use salts of other alkali metals and the acid radical maybe of a suitable character, to give an insoluble calcium compound in the resulting melt.

From the above it will be apparent to those skilled in the art that the invention described above is capable of wide variation with good results. Therefore, the invention is to be broadly construed and is to be limited only by the scope of the claims appended hereto.

What I claim is:

1. A method of producing alkali metalcyanides which comprises providing molten calcium cyanide, contacting the same with molten alkali metal carbonate to cause a reaction to take place and separating the resulting alkali metal cyanide from the solid reaction product without materially lowering the temperature.

I have 2. A method of producing alkali metal cyanides which comprises providing molten calcium cyanide, contacting the same with molten sodium carbonate to cause a reaction to take place and separating the resulting sodium cyanide from the solid reaction product without materially lowering the temperature.

3. A method of producing alkali metal cyanides which comprises providing a molten mixture of calcium cyanide and sodium chloride, and cont'a'cting the same with molten sodium carbonate to cause a reaction to take place.

4. A method of producing alkali metal-cyanides which comprises producing molten calcium cyanide, pouring the same, adding to the stream of calcium cyanide a stream of molten alkali metalsalt of an acid capable of forming an insoluble calcium salt to cause a reaction to take place, and solidifying the mixture.

5. A method of producing alkali metal cyanides which comprises producing molten calcium cyanide, pouring the same, adding to the stream of calcium cyanide a stream of molten sodium car bonate to cause a reaction to take place, and soliclifying the mixture.

6. A method of producing alkali metal cyanides which comprises producing molten calcium cyanide, pouring the same, adding to the stream of calcium cyanide a stream of molten alkali metal salt of an acid capable of forming an insoluble calcium salt to cause a reaction to take place, and solidifying the mixture by contacting the same with a cooled flaking drum. "7. A method of producing alkali metal cyanides which comprises producing molten calcium cyanide, pouring the same, adding to the stream of calcium cyanide a stream of molten sodium carbonate to cause a reaction to take place, and solidifying the mixture by contacting the same with a cooled flaking drum.

' 8. A method of making alkaline metal cyanide which includes the steps of reacting an alkaline earth metal cyanide with an alkali metal salt of an acid capable of forming an insoluble alkaline earth metal salt, in a liquid melt, and separating the insoluble solid alkaline earth metal salt from the molten alkali cyanide. I

9. The method of claim 8 in which the alkaline earth metal is calcium. 7

10. The method of claim-8 in which the acid is carbonic.

e 11. The method of claim 8 in which the alkaline earth metal is'calcium and the acid is carbonic.

12. The method of claim 8 in which the melt is maintained as a quiescent liquid for a sufficiently long time to permit the solids to settle and then decanting the supernatant molten alkali cyanide.

' 13. A method ofmaking sodium cyanide which includes the steps of fusing a mixture of alkaline earth metal'cyanide and an alkali salt of an acid capable of forming an insoluble alkaline earth metal salt, and separating the insoluble solid alkaline earth metal salt from the molten sodium cyanide.

Y 1 ERNEST C. MOFFETT. 

